KT120 in Audio Research Pre-amp?


I recently exchanged my totally worn out 6550C's for KT120 tubes from Tung Sol in my VT200 MkII. It required a small modification, I'll spare you the details, but it was a succesful operation, quite happy with the sound of the KT120's.
I have some spare KT120's and I was wondering.... is there any danger in replacing the Svetlana 6550C of my Audio Research Reference 3 for a KT120 tube? Since it is a risk-free replacement for most ARC-poweramps, I was wondering if this would be the same risk-free replacement for their pre-amps like a Ref3.
128x128midcall
Microstrip! Barely recognize you over here, relative to WBF! ;) May PM you over there for some advice...
so , no problem what I did two years ago , replaced the original 6550 tube by a NOS Tungsol black gitter , replaced in the REF 3 , and the CD7 .
regards Hans ( the Netherlands )
So how exactly did you get the KT120 into the VT200MkII? I was told by ARC it was not possible.